Brush filaments

ABSTRACT

Brush filaments having an outer surface which, distal from the filaments&#39; free ends, exhibits sudden directional changes which in use can effect a cleaning action additional to that due to the free ends of the filaments is disclosed.

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/142,772, filed Jul. 8, 1999.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to brush filaments, their method ofmanufacture and brushes incorporating them.

[0004] 2. Description of Related Art

[0005] Conventional brushes consist of a handle having at one end, abrush head including a plurality of filaments of natural fibre (e.g.animal bristles) or of synthetic material (e.g. nylon) which are ofuniform circular cross-section throughout their length. The length,lateral juxtaposition and material of the filaments are selected toprovide a desired flexibility for the free ends of the filaments, itbeing the free ends that in use are, in general, exclusively responsiblefor the cleaning efficacy of the brush.

[0006] Variations in shapes and designs of filaments are known. Theyinclude filaments bearing abrasive elements such as scales, serrations,and projections. C.f. U.S. Pat. No. 4,373,541. While these designs canimprove the cleaning action of the filament, they can be quite difficultto manufacture. Certain designs may also result in unacceptable flexuralstiffness and flexural recoverability of the filament.

[0007] The present invention aims to provide a new brush filament,which, in use, can effect improvements in cleaning, whilst maintainingrobust flexibility and strength.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIGS. 1a to 1 g are schematic illustrations of alternative formsof filaments according to the present invention.

[0009]FIGS. 2a to 2 g are schematic illustrations of modified versionsof the filaments depicted in FIGS. 1a to 1 g.

DETAILED DESCRIPTION OF THE INVENTION

[0010] According to the first aspect of this invention there is provideda brush head including a plurality of filaments each having across-section that, distal from the filament's free end, is not ofuniform circularity along the length of the filament. The cross-sectionmay be uniform but non-circular, or may be non-uniform but circular andhalf uniform, or may be half non-uniform but circular at all points andhalf circular, or may be both non-uniform but circular at all points onone half and circular on the other half. The cross-section may beuniform on one half and uniform but non-circular on the other half, orit may uniform on one half and non-uniform but circular at all points onone half, or it may be uniform on one half and non-circular andnon-uniform on the other half.

[0011] According to the second aspect of this invention there isprovided a brush head including a plurality of filaments each having anouter surface which, at least distal from the filament's free end,exhibits sudden directional changes which enable said outer surface ‘inuse’ to effect a cleaning action additional to that due to the free endof the filaments. Preferably said sudden directional changes provide thefilament with one or more abrading edges.

[0012] Each of some or all of the filaments has one or more of thefollowing characteristics:

[0013] (a) its exterior surface exhibits sudden directional changesproviding one or more edges which in use can effect a cleaning actionadditional to that due to the free end of the filament.

[0014] (b) a cross-section that is not of uniform circularity along thelength of the filament.

[0015] (c) the cross-section may be uniform but non-circular, or may benon-uniform but circular at all points, or may be both non-circular andnon-uniform.

[0016] A first example of a filament exhibiting one or morecharacteristics of this nature is shown as filament 15 a in FIG. 1a. Itis composed of a sequence of rectangular cross section parallelepipeds16 a of similar dimensions but alternating in direction so as to presentalternating larger and smaller widths 17 a, 18 a when viewed in sideelevation. The edges 19 a of the parallelepipeds 16 a provide in use acleaning action additional to that provided by the free end 20 a offilament 15 a.

[0017] A second example of a filament exhibiting a said characteristicis shown as filament 15 b in FIG. 1b. As with filament 15 a of FIG. 1a,this filament 15 b is composed of a sequence of rectangularcross-section parallelepipeds 16 b. However, in this example, theparallelepipeds 16 b are connected with their diagonal's co-linear withone another as shown. The edges 19 b of the diagonally alignedparallelepipeds 16 b provide in use a cleaning action additional to thatprovided by the free end 20 b of filament 15 b.

[0018] A third example of a filament exhibiting a said characteristic isshown as filament 15 c in FIG. 1c. This filament 15 c is composed of aseries of conical elements 16 c of similar dimensions surmounting oneanother. The base 19 c of each upper conical element can be spaced aboveor (as shown) level with the top of the conical element 16 c next belowit. Alternatively, each of the elements 16 c can be frusto-conical withits tip ‘cut-off’ by the base next above it. In use the circularperipheral edge of each base 19 c provides a cleaning action additionalto that provide by the free end 20 c of filament 15 c.

[0019] A fourth example of a filament exhibiting a said characteristicis shown as filament 15 d in FIG. 1d. This filament 15 d has itsexterior surface formed as a series of circular or semi circularcross-section encompassing a core of circular, square, rectangular orother polygonal cross-section. The rings 16 d are superimposed upon oneanother so as to be in mutual contact (forming a traverse cusp-likeinterval or transition between adjacent ring pairs). Alternatively,instead of being provided as individual mutually superimposedprotrusions, the rings 16 d can be provided as a single spiral or coilformation about the core as illustrated in FIG. 3d. In each such versionof the structure illustrated generally in FIG. 1d and FIG. 3d, thesudden transitions in direction for the cross-section provide in use acleaning action additional to that provided by the free end 20 d offilament 15 d.

[0020] Similar considerations apply to the fifth example of a filamentexhibiting a said characteristic is shown as filament 15 e in FIG. 1e.This filament 15 e is similar to the filament 15 d of FIG. 1d exceptthat its rings 16 e are longitudinally spaced apart to reveal the coreand provide additional transitional edges. As in that case, the rings 16e can alternatively be provided as a single, wide pitch, spiral or coilformation ‘wound’ about the core 18 e. In each such version of thestructure illustrated generally in FIG. 1e, the sudden transitions indirection for the cross-section and the resultant additional surfacesprovide in use a cleaning action additional to that provided by the freeend 20 e of filament 15 e.

[0021] A sixth example of a filament exhibiting a said characteristic isshown as filament 15 f in FIG. 1f. This filament 15 f has its exteriorsurface formed as a series of hemispherical elements 16 f of similardimensions surmounting one another. The circular peripheral edges of thebases 19 f of the hemispherical elements 16 f provide in use a cleaningaction additional to that provided by the free end 20 f of filament 15f.

[0022] A seventh example of a filament exhibiting a said characteristicis shown as filament 15 g in FIG. 1g. This filament 15 g is composed ofa series of spherical elements 16 g of similar dimensions surmountingone another. The base 19 g of each upper spherical element can be spacedabove or (as shown) level with the top of the spherical element 16 gnext below it. Alternatively, each of the elements 16 g can befrusto-spherical with its tip ‘cut-off’ by the base next above it. Inuse the sides of each sphere 16 g provide a cleaning action additionalto that provided by the free end 20 g of filament 15 g.

[0023] Additionally, for each of the examples described above and shownin FIGS. 1a to 1 g there is shown in FIGS. 2a to 2 g filaments where onehalf of the filament along its length is of regular uniform circularcross-section and the other half of the filament along its length ishalf of any of filaments 15 a to 15 g. In other words, the suddendirectional changes are substantially limited to an area extending alongone half of the circumference of the filaments and for the length of thefilaments. The uniform cross-section half of the filament will givegreater bend recovery to the filaments. The proportions described abovemay be varied and the uniform cross section need not necessarily becircular, it may be square or rectangular or any other uniform shape.

[0024] Particularly good results are achieved when the location of thesudden directional changes on the outer surface of the filaments aresubstantially limited to an area extending along 20 to 75% of thecircumference of the filaments and for the length of the filaments. Moreparticularly, the sudden directional changes are substantially limitedto an area extending along 30 to 60% of the circumference of thefilaments and for the length of the filaments.

[0025] The brush filaments according to the present invention can bemade from any plastics or polymer material, metal, wood, natural fiberor from any combination of these materials. Particularly preferredpolymer material is nylon or polyester. Examples of suitable nylon arenylon 6, nylon 6,6, nylon 6,10, nylon 6,12, nylon 6,9, nylon 10,10,nylon 11, nylon 12, copolymers thereof or mixtures thereof. Examples ofsuitable polyester are polyethylene terephthalate, polybutyleneterephthalate, polytrimethylene terephthalate and polypropyleneterephthalate (these latter two polyesters sometimes referred to as“3GT” or “PTT” polyesters), copolymers thereof or mixtures thereof.

[0026] A suitable method for making filaments according to the presentinvention is as follows.

[0027] An apparatus is constructed of two rolls, supported by shafts,and spaced a defined distance apart. The rolls are so configured torender sudden directional changes on the surface of a filament thatpasses between them. The first roll is a milling head, which is a metaldrum, approximately 20 mm in diameter, and is embossed. The embossingdesign determines the design of the filament. A particularly preferreddesign is made of vertical slots on the milling head, which have a“V”-shaped profile. This design creates indentations along the length ofthe filament.

[0028] The second roll can be identical to the first roll. In this case,the two rolls are aligned such that a filament passing between them isrendered into one of the embodiments depicted in FIGS. 1a to 1 b.

[0029] Alternatively, the second roll can have a smooth surface. In thiscase, filaments passing between the rolls will be rendered with suddendirectional changes limited to a defined circumference of the filament,such as depicted in FIGS. 2a to 2 g. The configuration of the rolls canbe adjusted to vary the circumference of the filament which receivesdirectional change (embossing) from about 20 to 75% of the totalcircumference.

[0030] Preferred designs of brush filaments according to the presentinvention will have from 1 to 100 indentations per lineal centimeter offilament, more preferably from 3 to 50. The indentations will preferablypenetrate into less than about 50% of the diameter of the filament.Penetration in excess of about 50% will typically degrade the flexuralrecoverability of the filament to an unsatisfactory extent.

[0031] The above-described embodiments and the features described and/orshown can be readily applied to many types of brushes, e.g. (withoutlimitation) toothbrushes, kitchen brushes, shoe brushes, clothes brushesand paint brushes and that some or all of the features described abovefor another embodiment. These, and other modifications and embodimentsof the invention, will be readily apparent to those skilled in this art.All such modifications and embodiments are to be deemed within the ambitand scope of the invention. In other words, the invention is not to bedeemed limited to the particular embodiment(s) hereinbefore describedwhich may be varied in construction and detail without departing fromthe scope of the patent monopoly hereby sought.

1. Brush filaments having an outer surface which, distal from thefilaments' free ends, exhibits sudden directional changes which in usecan effect a cleaning action additional to that due to the free end ofthe filaments, the location of said sudden directional changes beingsubstantially limited to an area extending along 20 to 75% of thecircumference of the filaments and for the length of the filaments. 2.Brush filaments according to claim 1 wherein the sudden directionalchanges are substantially limited to an area extending along 30 to 60%of the circumference of the filaments and for the length of thefilaments.
 3. Brush filaments according to claim 1 wherein the suddendirectional changes are substantially limited to an area extending alongone half of the of the circumference of the filaments and for the lengthof the filaments.
 4. Brush filaments according to claim 1 which are madefrom any plastics or polymer material, metal, wood, natural fiber orfrom any combination of these materials.
 5. Brush filaments according toclaim 5 wherein the polymer material is nylon or polyester.
 6. Brushfilaments according to claim 6 wherein the nylon is nylon 6, nylon 6,6,nylon 6,10, nylon 6,12, nylon 6,9, nylon 10,10, nylon 11, nylon 12,copolymers thereof or mixtures thereof.
 7. Brush filaments according toclaim 6 wherein the polyester is polyethylene terephthalate,polybutylene terephthalate, polytrimethylene terephthalate andpolypropylene terephthalate, copolymers thereof or mixtures thereof. 8.Brush filaments according to claim 1 wherein the sudden directionalchanges are created by indentations formed along the length of thefilament.
 9. Brush filaments according to claim 9 wherein there are from1 to 100 indentations per lineal centimeter of filament.
 10. Brushfilaments according to claim 9 wherein the indentations penetrate intoless than about 50% of the diameter of the filament.
 11. A brushcontaining brush filaments according to claim
 1. 12. Brush filamentsaccording to claim 1 which are made by passing substantially cylindricalfilaments between two rolls, at least one of said rolls being embossedand configured to render the sudden directional changes on the outersurface of the filaments.